1. Field of the Invention
The present invention relates to an image forming apparatus, a process cartridge that can be detachably mounted in the main body of the image forming apparatus, a developing device, a developer container, a method of improving the transmission of a developer-amount detection light through a developer container, a method of detecting the amount of developer in a developer container, a method of feeding a developer to a developer member, and a method of developing an electrostatic latent image formed on an electrophotographic photosensitive member.
2. Description of the Related Art
Image forming apparatuses using an electrophotographic process, such as printers and the like, perform image recording by uniformly charging a photosensitive drum, serving as an electrophotographic photosensitive member, forming an electrostatic latent image by performing selective exposure on the photosensitive drum, visualizing the electrostatic latent image by developing it using a toner, serving as a developer, transferring the obtained toner image onto a recording medium, and fixing the toner image on the recording medium by supplying the transferred toner image with heat and pressure.
Such apparatuses require toner replenishment and maintenance of various process means. As means for facilitating toner replenishment and maintenance, cartridges in which the photosensitive drum, charging means, developing means, cleaning means and the like are integrated within a frame have been practically used.
A developing device in such a process cartridge includes a developer-remaining-amount detection device for detecting the remaining amount of an accommodated developer. One of developer-remaining-amount detection methods is a light-transmitting remaining-amount detection method that is less expensive and has a simple configuration. In this method, the remaining amount of a developer accommodated within a container is obtained by causing detection light to pass through the container and measuring the time period of detection of the detection light.
The configuration of a conventional light-transmitting remaining-amount detection device will now be described with reference to FIGS. 13 and 14. As shown in FIGS. 13 and 14, a process cartridge 7 includes a photosensitive drum 1, serving as an image bearing member, a developer container or receptacle 25 accommodating a toner T, serving as a developer, to be supplied to the photosensitive drum 1, and a stirring blade 28b for stirring the toner T within the developer container 25 and conveying the toner T toward a supply roller 29.
After uniformly charging the surface of the photosensitive drum 1 by a charging roller 2, an electrostatic latent image is formed on the photosensitive drum 1 by projecting a laser beam corresponding to image information from a scanner unit (not shown) to the drum 1, and the toner T is supplied to the electrostatic latent image via the supply roller 29 and a developing roller 27, to form a toner image.
As shown in FIG. 14, detection light L emitted from a light emitting device 30a, serving as a light emitting member, passes through a first guide unit 31a made of a transparent material and enters the developer receptacle 25 from a first light-transmitting window 51a provided at the developer container 25.
The detection light L entering the developer container 25 leaves the developer container 25 from a second light-transmitting window 51b provided at the developer container 25. The detection light L leaving the developer container 25 reaches a photosensor 30b, serving as a photosensing member, via a second guide unit 31b made of a transparent material. The remaining amount of the toner T within the developer container 25 is detected based on the time period of detection of the detection light L by the photosensor 30b. 
A rotating feeding member 28 for feeding the toner T accommodated within the developer container 25 toward a developing member comprising the supply roller 29, the developing roller 27 and the like contacts an inner inclined portion 51c of the first light-transmitting window 51a and an inner inclined portion of the second light-transmitting window 51b at every rotation. That is, by wiping the inner inclined portions 51c and 51d of the first and second light-transmitting windows 51a and 51b by the stirring blade 28b, which is made of a flexible plastic sheet with mean wiping forces SK and SK′, respectively, the toner T adhering to the inner inclined portions 51c and 51d is cleaned to allow transmission of light.
In the above-described conventional approach, however, although the inner inclined portions 51c and 51d of the first and second light-transmitting windows 51a and 51b, respectively, are cleaned at every rotation of the rotating feeding member 28, it is impossible to completely remove the adhering toner T, and the toner T more or less remains. As a result, the transmission loss of light increases, and it is therefore necessary to increase in advance the intensity of the detection light L emitted from the light emitting device 30a in consideration of the transmission loss.